An existing LED point light source can only emit a point light spot with a single transmission shape. Typically, the transmitted light spot is of a nearly circular shape, or is of an oval shape as required. No matter whatever specific shape of a light spot is needed, this depends mainly on a cross-section shape of an exit pupil manufactured on the LED light source. In other words, light generally forms the light spot transmitted to a surface of an illuminated object after being intercepted via the pupil. Therefore, the shape of the transmitted light spot is determined by the cross-section shape of the pupil.
Nowadays, a large number of the light sources used on a red dot sight generally are LED point light sources, and the light spot transmitted generally is of the circular shape or the oval shape. However, to produce two light spots of different shapes, for example, to produce a round light spot outside a circular light spot, a general practice at present is to use a raster, thereby implementing interception of a cross section of the light spot emitted from an LED surface light source and transmitting the light spot with a specific form because of the interception of the raster. However, with the use of the LED surface light source, a lot of power is wasted due to use of the LED surface light source. Furthermore, only one of the circular light spot and the light spot with a specific shape produced due to a raster effect, rather than both of them, can be used at a time. If they are used simultaneously, an extra light path system is needed, which may make the whole light path complex. Particularly when only one light spot with a specific shape is needed, complexity of operation may be increased, and reliability of the sight is reduced.
Most of the existing red dot sights use batteries. For example, a lithium battery can provide electric energy required by the operation of a red dot module. The batteries have limited service lifetime and need to be replaced, so that use cost is increased. Furthermore, in the process of using, due to the change of illumination of external environment, supplied current or voltage of the batteries needs to be adjusted by means of a regulating switch so as to implement adjustment of the brightness of an output light of the red dot module. For example, when the environment brightness is enhanced, the brightness of the output light of the red dot module needs to be increased. Otherwise, the brightness of the output light of the red dot module needs to be decreased.
Such red dot sight relies on batteries to supply power no matter in the day or at night. Consequently, replacement of the batteries increases the use cost.
For the existing red dot sight, a dustproof cover is generally provided at the exit pupil. Opening or closing the dustproof cover is implemented by upside down of a coupling pin. Opening degree completely depends on an extent that a cover plate is opened by manpower. The cover plate cannot be opened quickly at one go. The cover plate may need to be opened twice and even thrice because the cover plate may be not opened in place once. In this process, fingers may touch other parts, thereby producing vibration, which is not beneficial to stable adjustment of the sight.
Additionally, unlocking an existing installation card track generally is implemented by drawing a lock catch to a trigger portion of a cam handle. Improper force direction cannot effectively apply human power to the lock catch sufficiently. As a result, opening the lock catch needs larger strength and proper angle, and thus the operation is not quickly enough.
The foregoing information is merely disclosed to facilitate understanding of background of the present disclosure. Therefore, the foregoing information may include information not constituting the prior art known to those of ordinary skill in the art.